It was a difficult early session for the favourites at the 2019 Miami Open Masters on Friday, with several top-class names eliminated.
No. 5 men's seed Kei Nishikori exited the competition after falling in three sets to Dusan Lajovic, and Gilles Simon was knocked out by countryman Jeremy Chardy.
Venus Williams swept past No. 24 women's seed Carla Suarez Navarro, and there was further misery for seeded players as Aryna Sabalenka, Anastasia Pavlyuchenkova and Sofia Kenin crashed out.
The trio were defeated by Ajla Tomljanovic, Viktoria Kuzmova and Bianca Andreescu, respectively.
Reigning men's champion John Isner won a close battle with Lorenzo Sonego in straight sets.
Women's top seed Naomi Osaka was comfortable as she progressed against Yanina Wickmayer after losing the second set.
 John Isner (USA) def. [Q] Lorenzo Sonego (ITA), 7-6(2), 7-6(7)
Dusan Lajovic (SRB) def.  Kei Nishikori (JPN), 2-6, 6-2, 6-3
 Kyle Edmund (GBR) def. Ilya Ivashka (BLR), 6-3, 6-2
 Borna Coric (CRO) def. Roberto Carballes Baena (ESP) 7-6(7), 0-6, 6-2
 Nikoloz Basilashvili (GEO) def. Mischa Zverev (GER), 6-3, 6-2
Federico Delbonis (ARG) def.  John Millman (AUS), 7-5, 3-6, 7-6(2)
Jeremy Chardy (FRA) def.  Gilles Simon (FRA), 6-4, 6-2
 Naomi Osaka (JPN) def. [Q] Yanina Wickmayer (BEL), 6-0, 6-7(3), 6-1
Venus Williams (USA) def.  Carla Suarez Navarro (ESP), 7-6(4), 6-1
Ajla Tomljanovic (AUS) def.  Aryna Sabalenka (BLR), 6-3, 6-4
 Su-Wei Hsieh (TPE) def. Alison Riske (USA), 6-2, 7-5
Viktoria Kuzmova (SVK) def.  Anastasia Pavlyuchenkova (RUS), 6-7(5), 6-4, 7-5
Bianca Andreescu (CAN) def.  Sofia Kenin (USA), 6-3, 6-3
 Anett Kontaveit (EST) def. Amanda Anisimova (USA), 6-3, 1-6, 6-4
 Elise Mertens (BEL) def. Pauline Parmentier (FRA), 6-2, 7-5
Marketa Vondrousova (CZE) def.  Jelena Ostapenko (LAT), 7-5, 6-1
 Daria Kasatkina (RUS) def. [WC] Cori Gauff (USA), 6-3, 6-2
Full results and schedule are available from the tournament's official website.
Early Friday Recap
Nishikori crashed out of the Miami Open as he faltered after an easy first set against Lajovic.
The Japanese star took the opening set 6-2, but that's as good as it got for one of the top seeds.
Both players struggled to produce aces, but neither man was wasteful on serve, and faults were kept to a minimum.
Lajovic converted five of his nine break points in the match, and he sprinted away to victory in the final two sets.
Tennis TV shared the winning moment after an energetic rally:
Isner was forced to battle in his match with Sonego, and the champion progressed after winning two tiebreaker sets.
The American once more used the power and accuracy of his serve to give him a telling advantage.
Isner landed 20 aces on his way to the win, and Sonego had no answer to the 33-year-old's incredible first serve.
Venus Williams flexed her muscle against Navarro as she forced her way into the next round.
A hard-fought opening set saw the legend edge a tiebreaker, but Williams was rampant as she claimed the second 6-1.
Osaka will be disappointed she allowed Wickmayer to rally in their match. The No. 1 seed produced a clean sweep to win the opener 6-0 but inexplicably dropped the second in a tiebreak situation.
However, Osaka was clinical as she found her rhythm, closing out the final set with little fuss.